THE INFLUENCE OF AGE AND EXPERIENCE ON BREEDING PERFORMANCE OF THE ANTARCTIC FULMAR, FULMARUS-GLACIALOIDES

Inexperienced birds laid smaller eggs which hatched at later dates and with a lower success than those of experienced birds. Chicks reared by inexperienced pairs were fed less frequently, attained a lower asymptotic weight at a higher rate and weighed less at fledging than the chicks of experienced pairs. No differences between inexperienced and experienced pairs were observed in the total amount of food brought to the chick, maximum weight attained by the chick, length of the wing at fledging or fledging success. Breeding performance did not improve with age or experience after the 1st successful breeding attempt but size of the egg did. Unsuccessful birds were more likely to change mate than successful ones. Chick growth parameters were highly variable between the 2 seasons studied, and between individual pairs which tended to produce siblings of the same quality. Birds more often failed to return to the colony to breed the following year after a first breeding attempt than after several. These results suggest that by their 1st breeding attempt the birds have probably attained similar foraging abilities to experienced birds, but the pair requires at least a further year to coordinate its breeding schedule. Because they need a longer period between breeding attempts, the inexperienced breeders could pay a greater cost of reproduction than experienced birds. After a 1st successful breeding, reproductive performance will be influenced largely by the quality of the pair, and also by annual fluctuations in food availability. -from Author